Analysts expected a challenge from Tammy, Melissa McCarthy's latest comedy. The film struggled with just $21.2 million, good for second place.

Box office has been on a ticket sales slide all summer, and moviegoers appeared more interested in pyrotechnics outside than inside the cineplex this weekend.

Ray Subers of Box Office Mojo notes that the holiday isn't typically a great one for moviegoing, as families hit the road on the long weekend.

"These titles would likely have earned a bit more on a traditional Friday," he says.

Still, the industry has been slumping for more than two months. June's ticket sales plummeted 16% from the same month last year, according to the site. While movies are enjoying healthy debuts, ticket sales are dropping off 70% and more per weekend as movies cannibalize each other in a packed slate.

It didn't help that this weekend's three new films came with little firepower. McCarthy has been one of the industry's most bankable comedians. But the $20 million movie, directed by husband Ben Falcone, mustered just a 26% approval rating from critics, says survey site Rotten Tomatoes. More troubling: It earned just a C-plus from moviegoers, says CinemaScore, an ominous sign for its long-term prospects.

Not that other films caused a ruckus. The horror film Deliver Us From Evil took third place with $9.5 million, meeting most analysts' modest expectations.

The sequel 22 Jump Street claimed fourth with $9.4 million, while the animated sequel How to Train Your Dragon 2 was fifth with $8.8 million.

The only other major newcomer, the sci-fi film Earth to Echo, landed in sixth place with $8.3 million. Final figures are expected Monday.

Says Rentrak's Paul Dergarabedian: "The Fourth of July holiday went off with more of a whimper than a bang."